Unless otherwise indicated herein, the description provided in this section is not itself prior art to the claims and is not admitted to be prior art by inclusion in this section.
A typical cellular wireless network includes a number of base stations each radiating to define a respective coverage area in which user equipment devices (UEs) such as cell phones, tablet computers, tracking devices, embedded wireless modules, and other wirelessly equipped communication devices, can operate. In particular, each coverage area may operate on one or more carriers each defining a respective frequency bandwidth of coverage. In turn, each base station may be coupled with network infrastructure that provides connectivity with one or more transport networks, such as the public switched telephone network (PSTN) and/or the Internet for instance. With this arrangement, a UE within coverage of the network may engage in air interface communication with a base station and may thereby communicate via the base station with various remote network entities or with other UEs.
Further, a cellular wireless network may operate in accordance with a particular air interface protocol or “radio access technology,” with communications from the base stations to UEs defining a downlink or forward link and communications from the UEs to the base stations defining an uplink or reverse link. Examples of existing air interface protocols include, without limitation, Orthogonal Frequency Division Multiple Access (OFDMA (e.g., Long Term Evolution (LTE)), Code Division Multiple Access (CDMA) (e.g., 1×RTT and 1×EV-DO), Wireless Interoperability for Microwave Access (WiMAX), and Global System for Mobile Communications (GSM), among others. Each protocol may define its own procedures for registration of UEs, initiation of communications, handover between coverage areas, and other functions related to air interface communication.
In accordance with the LTE protocol, for instance, when a UE enters into coverage of a base station, the UE may engage in attach signaling with the base station, by which the UE would register to be served by the base station on a particular carrier. Through the attach process and/or subsequently, the base station and supporting network infrastructure may establish for the UE one or more bearers, essentially defining logical tunnels for carrying bearer data between the UE and a transport network such as the Internet. Once attached with the base station, a UE may then operate in a “connected” mode in which the base station may schedule data communication to and from the UE on the UE's established bearer(s).
Moreover, a network may include a plurality of network controllers that function to facilitate setup and management of bearers through which UEs can engage in data communication, to facilitate tracking and status of UEs throughout the network, and to facilitate paging of UEs for incoming communications. In an LTE network, such controllers can be referred to as mobility management entities (MMEs). Each MME may serve one or more portions of the network known as tracking areas, each of which may include a number of base stations known as eNodeBs arranged to provide coverage for UEs. Thus, an MME may serve the UEs that are operating within coverage of an eNodeB in a tracking area served by the MME.
When a network controller serves a UE, the network controller may store a context record for the UE. The context record may include information that helps the network controller serve the UE, such as data specifying a subscription profile for the UE, data specifying capabilities of the UE, and/or data specifying service status of the UE such as particular bearers or other connections that are established for the UE, among others. The network controller may then make use of that context record while serving the UE. For example, if the UE seeks to engage in a particular type of communication, the network controller may refer to the UE's context record to determine if that type of communication is authorized by the UE's subscription profile and may allow the communication if the particular type of communication is authorized. In another example, as the UE transitions between an active or “connected” mode in which the UE has an assigned radio link and an “idle” mode in which the UE does not have an assigned radio link, the network controller may receive signaling indicative of that transition and may update the UE's context record to indicate whether the UE is currently operating in the connected mode or in the idle mode. Other examples may also be possible.
Further, an air interface protocol may include a user plane protocol stack and a control plane protocol stack to organize data carried between a respective base station and UEs. In accordance with LTE, for instance, the user plane protocol stack may be responsible for user data transmission and may include a Packet Data Convergence Protocol (PDCP) layer, a Radio Link Control (RLC) layer, and a Medium Access Control (MAC) layer. Additionally, the control plane protocol stack may be responsible for control signal transmission and may also include a PDCP layer, a RLC layer, and a MAC layer, as well as a Radio Resource Control (RRC) layer.
The various layers may have different roles in organizing the data as the data is communicated between layers in the protocol stacks using logical channels and transport channels. For example, an Internet protocol (IP) packet header may contain nonessential control information that increases the size of the header and thus increases the difficulty to efficiently transmit IP packets over a radio link having a relatively small bandwidth. Thus, the PDCP layer may perform a header compression operation for the purpose of reducing size of the IP header before transmission of the data at a physical (PHY) layer. As such, the base station may sequentially process data through one or more upper layers down to the physical layer at which the base station processes the data for communication over an air interface to a UE.